Thanks for the quick response. Our supporter of Diamant enabled some tracing, but I don't know where and how. I can just see that these logs have Limilabs :/
logs:
2022/02/01 13:03:39.459 P 001660 T 000001 "Error: ServerException - HResult: -2146233088"
2022/02/01 13:03:39.459 P 001660 T 000001 "Beende SMTP-Connect: Ende"
2022/02/01 13:03:39.459 P 001660 T 000001 "Abschluss Limilabs Log und SendMail Builder"
2022/02/01 13:03:39.459 P 001660 T 000001 "ReturnType: "
2022/02/01 13:03:39.459 P 001660 T 000001 "-2146233088"
Is there a more exact manual how to enable logging? Which file do I have to modify?